1. Field of the Invention
The present invention relates to a detector for detecting a movable body such as an automatic door catching a foreign material, to a foreign material detector for a sliding door which detects a foreign material caught between a door panel and a vehicle body of a vehicle and a detecting method thereof.
2. Description of the Related Art
Among vehicles referred to as recreation vehicles and generally including wagons and vans, there is a vehicle in which a so-called automatic sliding door device, which allows a door panel to slide forward and backward along a side wall portion of a vehicle body by means of a driving force of a motor and opens and closes an entrance formed in the side wall of the vehicle body, is adopted. In this device, by operating an operation switch provided in the vicinity of a driver's seat and at a predetermined location of back seats, the motor is driven and the door panel is moved.
Further, among this kind of automatic sliding door devices, there is an automatic sliding door device which includes a foreign material detector which detects a state of catching a foreign material existing between a door panel and a vehicle body at the time of closing movement of the door panel.
The foreign material detector applied to the above-described automatic sliding door device includes a pressure sensor which is elongated along a front end portion (i.e., an end portion of a closing movement direction side) of a door panel and in which a plurality of wires are disposed inside a hollow outer cover portion thereof along a longitudinal direction of the pressure sensor. This pressure sensor is structured such that, when the outer cover portion receives a pressing force and is elastically deformed, the wires disposed within the outer cover portion are bent and come into contact with each other, accompanied with the elastic deformation of the outer cover portion. Then, by detecting a change in an electric resistance at the time that the wires came into contact with each other, for example, a fact that the pressing force acted upon the outer cover portion, i.e., a fact that a foreign material abutted the front end portion of the door panel which moves in a closing direction, is detected.
Meanwhile, among vehicles to which the above-described sliding doors are applied, there is a vehicle, in which a so-called “vent hem structure” in which a front end portion of a door panel is formed in a plate form which is sufficiently thinner than a main body portion of the door panel, is adopted. In this structure, when the door panel closes an entrance, the front end portion of this door panel is located at a vehicle interior side of a vehicle body (a side wall of the vehicle), and also opposes the vehicle body along a substantial right and left direction of the vehicle (a substantial vehicle transverse direction).
In a case in which the vent hem structure is adopted in a vehicle, the front end portion of the door panel opposes the vehicle body at a vehicle interior side in a closed state of the door panel. Thus, if a coating which is similar to that coated on the vehicle body is applied up to a tip end of the door panel, even in a case in which a gap is formed between the entrance and the door panel, the coating applied to the front end portion of the door panel can be seen in an inner side thereof. This feature contributes to improve an appearance quality of a vehicle.
In a vehicle in which such a vent hem structure is adopted, the front end portion of the door panel faces the vehicle body at the vehicle interior side in the closed state of the door panel, and the door panel moves toward a vehicle front and then shifts toward a vehicle interior side immediately before the door panel closes up the entrance. This feature is different from that of a structure, in which a door panel simply moves in a substantial longitudinal direction of a vehicle.
Therefore, concerning the above-described foreign material detector, improvement in a detection performance has been longed with respect to catching a foreign material accommodating with the above-described vent hem structure.